Performance: Cache DB transaction locking of Karma::ActivityLog.add.

app/models/karma/activity_log.rb

@@ -20,6 +20,15 @@ add karma activity log of an object
       object_id = ObjectLookup.by_name(object)
     end
 
+    # scheduler transactions causes a lot of calls
+    # so we try to cache the add process
+    # to skip the time loss of the transaction
+    # to increase performance
+    if !force
+      cache = Cache.get("Karma::ActivityLog.add::#{activity.once_ttl.seconds}::#{action}::#{user.id}::#{object}::#{o_id}")
+      return cache if cache
+    end
+
     Karma::ActivityLog.transaction do
       last_activity = Karma::ActivityLog.where(user_id: user.id).order(id: :desc).lock(true).first
       latest_activity = Karma::ActivityLog.where(
@@ -48,6 +57,10 @@ add karma activity log of an object
         score:            activity.score,
         score_total:      local_score_total,
       )
+
+      if !force
+        Cache.write("Karma::ActivityLog.add::#{activity.once_ttl.seconds}::#{action}::#{user.id}::#{object}::#{o_id}", true, expires_in: activity.once_ttl.seconds)
+      end
     end
 
     # set new karma level